1. Field of the Invention
The present invention relates to a coreless motor with speed-reducer mechanism.
2. Description of the Related Art
To attain a speed-reduced motor output, a speed-reducer mechanism is generally provided between a motor output shaft and a desired output shaft. The speed-reducer mechanism is disposed outside or inside the motor. Even in the case of speed-reducer mechanisms disposed inside the motor, most of them are merely disposed inside a motor housing, but disposed outside basic motor components such as an armature and a rotor (Japanese Laid-open Patent Publication No. 8-186955).
The advantages of an arrangement having a motor and a gear head (speed-reducer mechanism) both incorporated in the same housing as disclosed in the just-mentioned patent publication are that intermediate component parts can be eliminated, which are required for coupling and positioning the motor and the speed-reducer mechanism when they are constructed independently of each other, and that an  operation for positional adjustment of the motor and the speed-reducer mechanism can be eliminated, resulting in a corresponding reduction of man-hour of assembly.
With the arrangement disclosed in Japanese Laid-open Patent Publication No. 8-186955, however, a downsizing of the motor can only slightly be achieved by the one-piece design of the motor and the speed-reducer mechanism. This indicates that a drastic revision including improvement in motor structure is required to achieve a further downsizing of the motor integrated with the speed-reducer mechanism, i.e., to further reduce the entire motor length.